18O isotopic study of photo-induced formation of peroxide species on cubic Nd2O3

Photo-induced formation of peroxide species on cubic Nd2O 3 was studied by in situ microprobe Raman spectroscopy using 18O as a tracer and a 325-nm laser as an excitation source. The results confirmed that the peroxide ions were formed through photooxidation of the lattice oxygen species in neodymium sesquioxide by molecular oxygen species. Under UV excitation (λ = 325 nm), the reaction between O2 and O2- could take place at room temperature. A fast oxygen exchange between the peroxide ions and the lattice oxygen species in Nd2O 3 took place under the experimental conditions studied. Also, bulk lattice oxygen species in Nd2O3 could migrate to the surface layer and participate in the formation of peroxide ions. The migration of lattice oxygen species and the oxygen exchange between lattice oxygen and peroxide ions were promoted by UV laser irradiation. ? 2014 Dalian Institute of Chemical Physics, the Chinese Academy of Sciences